Electrically operated pump



Jan. 24, 1950 Q KER 2,495,598

ELECTRICALLY OPERATED PUMP Filed Dec. 19, 1945 INVEN TOR.

Patented Jan. 24, 1950 ELECTRICALLY OPERATED PUMP Leland 0. Parker, Elmira, N. Y., assignor to Bendix Aviation Corporation, Elmira Heights, N. Y., a corporation of Delaware Application December 19, 1945, 'Serial No. 635,953 (oi. 172 12s) 6 Claims. 1

The present invention relates to an electrically operated electromagnetic motor for a fluid pump and more particularly for a plunger type of pump especially adapted for operation without attention over long periods of time as for instance pumps for compressing fluid refrigerants.

It is an object of the present invention to provide a novel electrically operated pump which is eiiicient and reliable in operation while being simple and economical in construction.

It is another-object to provide such a device which has a minimum number of moving parts.

It is a further object to provide such a device in which the pumping operation is timed by means of a relay which is controlled electrically by the movement of the pump piston.

It is another object to provide such a device which is adapted for operation by alternating current such as commonly supplied for domestic use.

Further objects and advantages will be apparent from the following description taken in connection with the accompanying drawing in which:

Fig. 1 is a side elevation partly in section of a preferred embodiment of the invention, the electrical circuits being shown diagrammatically; and

Fig. 2 is a similar view of a second embodiment of the invention.

In Fig. 1 of the drawing there is illustrated a cylinder i of non-magnetic material having an inlet conduit 2 coupled thereto by a fitting 3, and an outlet conduit 4 coupled to the opposite end of the cylinder by a fitting 5 which also serves to clamp a check valve 6 to the end of the cylinder. 1

A hollow piston 1 of highly permeable magnetic material such as Armco ingot iron is slid ably fitted in the cylinder i with a suitable working clearance, and has a check valve 8 mounted on its upper end. A spring 9 in the upper end of the cylinder normally maintains the piston 1 at the lower end of its stroke, and a solenoid ll surrounding the cylinder is arranged to attract the piston I to actuate it in its power stroke.

Means for energizing the solenoid II is provided in the form of a source of alternating current represented by the supply mains [2, I3, the

main l2 being connected to one end of the solenoid through a pair of relay contacts I 4, l5 and conductor l6 while the main I3 is connected directly to the other terminal of the solenoid. Means for controlling the relay contacts l4, l5 so as to open the contacts at the end of the power stroke of the piston and close the contacts at the end of the idle stroke thereof is provided in the form of a coil ll mounted on the cylinder I in position to surround the piston when it is at the end of its idle stroke, and a relay electromagnet Hi the energization of which is controlled by said coil. For this purpose one terminal of the coil I1 is connected by a lead l9 to the supply main l3, while a lead 2| connects the other terminal of coil l I to one end of the relay electromagnet 18, the opposite end of said electromagnet being connected by a lead 22 to the supply main l2. The coil I1 is so designed that when the piston 1 is located thereimthe coil becomes a choke coil for the alternatingcurrent supplied to the pump, substantially preventing the flow of current through the rela coil It. When the piston is withdrawn therefrom, however, the inductance of the coil is so reduced as to permit passage of current sufilcient to actuate the relay. This design of the coil l1 causes its attraction for the piston 1 to be very small so that it does not interfere substantially with the action of solenoid I l on the piston.

A switch 23 is preferably placed in one or both of the supply mains in order to disconnect the pump when it is desired to place it out of op eration.

In the operation of the device, starting with the parts in the positions illustrated in Fig. 1, closure of the main control switch 23 supplies altematlng current to the mains l2, l3, and since the contacts ll, [5 are closed, the solenoid H is energized to attract the piston l upwardly, compressing the sprin 9. The action of the check valves 8 and 6 is such that this motion of the piston causes fluid trapped above the check valve 8 to be ejected through the check valve 6 into the discharge conduit 4, while additional fluid is drawn into the cylinder l beneath the piston 1 through the inlet conduit 2.

Closure of the switch 23 also completes the circuit from the source of alternating current supply through the choke coil l1 and the relay electro-magnet I 8, but since initially the piston 1 is located within the coil ll, the inductance of the coil is raised thereby to such a value that the alternating current is prevented from passing through the coil in any substantial amount. The electro-magnet I8 is accordingly not energized and contacts I, [-5 remain closed. When the piston 1 moves up under the action of solenoid II, it is drawn out of the choke coil i1 whereby the inductance of the coil is reduced to a small value. The alternating current is thus permitted to flow through the coil and the electro-magnet |8 which consequently opens contacts l4, l and deenergizes the solenoid II. The spring 9 thereupon returns the piston 1 to its idle position at which time the fluid in the cylinder'l below the piston 1 passes up through the check valve 8 to occupy the space above th piston. When the piston returns into the choke coil H, its inductance is again raised to a point where the flow of alternating current therethrough is substantially interrupted, whereupon the electro-magnet |8 allows the relay contacts i4, i5 to close and the operation is repeated.

In Fig. 2 of the drawing there is illustrated an embodiment of the invention in which the inductive effect ofthe piston is used to generate a current which actuates the control relay. As there shown, a cylinder 3| of non-magnetic material has an inlet conduit 32 clamped to one end by a fitting 33, and an outlet conduit 34 clamped to the opposite end by a fitting 35, a check valve 36 being located in the outlet end of the cylinder.

A piston 31 of highly permeable magnetic material is slidably mounted in the cylinder 3| and has a check valve 33 fixed on its upper end. A spring 39 urges the piston toward its lower or idle position as illustrated, and a solenoid 4| fixed on the cylinder 3| is arranged to raise the piston 31 against the pressure of the spring 33 on its power stroke.

Solenoid 4| is arranged to be energized by alternating current from supply mains 42, 43, main 42 being connected to one end of the solenoid through relay contacts 44, 45 and conductor 45, while main 43 is connected directly to the opposite terminal of the solenoid.

Means for controlling the energization of the solenoid 4| are provided comprising a coil 41 fixed on the cylinder 3| in such a position that the piston 31 enters the coil in its discharge stroke. The terminals of coil 41 are connected by leads 48, 49 to a relay electro-magnet 5|, a suitable amplifying device indicated generally by numeral 52 being interposed therebetween if found necessary or desirable. Current rectifying means may also be incorporated in the amplifier 52 if desired in which case the relay comprising coil 5| and contacts 44, 45 may be designed as a direct current relay instead of an alternating current relay. A manually operable switch 53 is preferably provided for interrupting the connection of one or both of the mains 42, 43 with the power supply.

In the operation of this embodiment of the invention, closure of the manual switch 53 supplies alternating current to the mains 42, 43, and since contacts 44, 45 are closed the solenoid 4| is energized, and the piston 31 is attracted upwardly,

pushing ahead of it the fluid trapped in the cylincler 3| above the piston which fluid is thereby discharged through the outlet conduit 34 while additional fluid is drawn into the cylinder 3| through the inlet conduit 32. When the piston 3! enters the coil 41, the reversalsof polarity of the piston caused by the alternations in flux of the coil 4| as energized by the alternating current supply generate an alternating current in the coil 41 which may be amplified and/or rectified by the amplifier 52 and used to energize therelay electro-magnet 5|. Contacts 44, 45 are thereby opened, deenergizing the solenoid 4| and permitting the spring 33 to return to idle position, during which stroke the fluid in the cylinder 3| below the piston passes up through the piston and check valve 33 into the upper part of the cylinder. Deenergization of the solenoid 4| demagnetizes the piston 31 so that the generation of current in coil 41 ceases whereby relay contacts 44, are permitted to close and the operation is repeated.

Although but two embodiments of the invention have been shown and described in detail, it will be understood that other embodiments are possible and various changes may be made in the design and arrangement of the parts without departing from the spirit of the invention as defined in the claims appended hereto.

It will be understood that in both embodiments of the invention the design and composition of the piston and its actuating solenoid will be so related to the frequency and voltage of the current supply as to provide adequate propulsive force for the piston to overcome the back-pressure of the fluid and the forceof the return spring.

It will further be understood that the length of stroke of the piston I may be increased to any desired extent by suitably retarding the action of the control relay in any well-known manner as by the incorporation of copper slugs, condensers, etc.

What is claimed is:

1. In an electromagnetic motor for a fluid pump a non-magnetic cylinder, a piston of magnetic material slidable in the cylinder, a spring urging the piston toward one end of the cylinder, a solenoid surrounding the cylinder adapted when energized to move the piston against the spring toward the other end of the cylinder, means for energizing said solenoid including a source of alternating electrical current, a control coil surrounding the cylinder in position such that reciprocation of the piston in the cylinder causes it to move into and out of said coil, an alternating current relay comprising an electro-magnet and normally closed contacts which are opened by energization of said electro-magnet, and connections from the control coil to the electro-magnet of the relay for energizing said electro-magnet by means of alternating current flowing through said control coil.

2. An electromagnetic motor as set forth in claim 1 including further, means whereby the change in the inductive relation of the piston with respect to the control coil due to reciprocation of the piston varies the flow of current through said coil.

3. An electromagnetic motor as set forth in claim 1 including further means for connecting said control coil and relay electro-magnet in series to said source of alternating current, said control coil being so arranged that movement of the piston by the solenoid withdraws the piston from the coil, thereby reducing the reactance of the coil to alternating current sufiiciently to allow current to flow therethrough to actuate the relay electro-magnet.

4. An electromagnetic motor as set forth in claim 1 in which the control coil is so arranged that movement of the piston by the solenoid causes the piston to enter the coil and thereby induce a current in the coil which actuates the relay to deenergize the solenoid.

5. An electromagnetic motor including a solenoid, a source of alternating current for energizing said solenoid, a reciprocable member of magnctic material actuated thereby, a coil arranged to surround said reciprocable member during a portion of its stroke so as to be in inductive relation therewith, and means actuated by ourternating current relay energized by current gen- 10 erated in said coil for deenergizing the solenoid.

' LELAND C. PARKER.

6 REFERENCES CITED The following references are of record in the file of this patent:

5 UNITED STATES PA'I'ENTS Number Name Date 1,596,468 Wallace Aug. 1'7, 1926 1,737,388 Redmond Nov. 26, 1929 2,286,176 Boisselier June 9, 1942 2,293,684 Holthouse Aug. 18, 1942 2,322,913 Best et al July 29, 1943 

